JP2011020893A - Firing method for molded product and holding tool for firing the molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a sintered product having no cracks or warping, and to dispense with the use such as of cold isostatic press (CIP), which increases the number of steps for producing a molded product, in order to simplify the process. <P>SOLUTION: A molded product of a plate form is fired in a firing furnace to produce a sintered plate. The molded product is formed into a polygonal plate, and the molded product is fired in the state that the molded product is made to stand by a holding tool so that one corner of the molded product faces vertically downward. This means that the lowest corner of the polygonal plate of the molded product is received by the holder member of the holding tool, and one main face of a pair of main faces of the molded product is received by the support member of the holding tool. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method of firing a molded body to obtain a sintered body used as a vapor deposition material such as a sputtering method, an electron beam vapor deposition method, and an ion plating method, and to hold the molded body during firing of the molded body. It is related with a holder.

  Conventionally, when a plate-shaped molded body is fired, it is fired in a firing furnace in a state where the flat surface (main surface) having the widest area of the molded body is in contact with the floor plate, that is, in a flat state. At this time, in order to reduce the friction between the molded body and the floor plate, a floor powder, a block, or the like is interposed between the molded body and the floor plate.

  However, in the above-described method for firing a molded body, the molded body may be contaminated with bed powder or blocks. Further, in the above-mentioned method of firing the molded body, even if a floor powder or a block is interposed between the molded body and the floor plate, the friction generated between the molded body and the floor powder is still large. There was a problem that cracking occurred or warpage occurred. Furthermore, in the above-mentioned method for firing a molded body, since the molded body is in contact with the spread powder or block over a wide area, the number of molded bodies accommodated in the firing furnace is reduced, the processing amount is reduced, and the firing speed is slow. In addition, there is a problem that the cooling time becomes longer.

  In order to eliminate these points, after forming a mixture of an indium compound and a tin compound into a plate shape, the plate-like molded body is put in a firing furnace in a standing state, and both surfaces of the main plate surface of the plate-shaped molded body are placed. A method of firing ITO is disclosed in which the material is fired by exposing it to a furnace atmosphere (see, for example, Patent Document 1). In the ITO firing method configured in this way, an ITO sintered body free from warpage and color unevenness can be fired, and a flat sintered body can be obtained with a high yield.

In addition, using a press mold in which a plate-like material independent of the lower punch is interposed on the lower punch of the mold press, the ceramic powder is pressed at a pressure of 100 kg / cm ² (10 MPa) to 300 kg / cm ² (30 MPa). After pressing the mold with a die to prepare a molded body having a molding density of less than 50%, the powder press molded body is taken out integrally with the plate-like body, and then only the molded body is vacuum-sealed, and 1 ton / cm ² (100 MPa) or more A method of manufacturing a ceramic target that is fired after a hydrostatic press (CIP) process is performed at a pressure of 50 ° C. for a compact density of 50% or more is disclosed (for example, see Patent Document 2). With the ceramic target manufacturing method configured as above, it is possible to manufacture a target that is free of cracks and warpage, has excellent yield and production speed, and has excellent sputter characteristics. That.

JP-A-8-169770 (Claims 1 and 2, paragraphs [0005] and [0026]) JP-A-6-182732 (Claim 1, paragraph [0008])

  However, in the above-described conventional ITO firing method disclosed in Patent Document 1, when the plate-shaped molded body is placed in the furnace with the side surface of the plate-shaped body facing down, all of the side surfaces of the plate-shaped molded body are laid in the furnace. Therefore, there is a problem that the friction generated between the plate-like molded body and the base plate is large, and the sintered body is cracked or warped. Moreover, in the manufacturing method of the ceramic target shown by the said conventional patent document 2, the hydrostatic press (CIP) process is performed with respect to a molded object in multiple times, and the process for producing a molded object is complicated. There is a problem that the man-hour increases and the manufacturing cost increases.

  A first object of the present invention is to provide a method for firing a molded body and a holder for firing the molded body, which can obtain a sintered body free from cracks and warpage. The second object of the present invention is to eliminate the use of an isostatic press (CIP) or the like that increases the number of steps for producing a molded body, and can simplify the process, and a method for firing the molded body and firing the molded body. It is to provide a holding tool. A third object of the present invention is to provide a method for firing a molded body and a molded body that can suppress the occurrence of uneven color and improve the density of the sintered body by allowing gas to escape from the molded body relatively smoothly. The object is to provide a holder for firing. The fourth object of the present invention is to provide a method for firing a molded body and a holder for firing the molded body, which can greatly increase the temperature rising rate of the molded body and the temperature lowering rate of the sintered body during firing. There is to do.

  According to a first aspect of the present invention, there is provided a method for producing a plate-like sintered body by firing a plate-like formed body in a firing furnace, wherein the formed body is formed into a polygonal plate shape. The molded body is fired in a state where it is held upright and held by a holder so that the protruding top is vertically downward.

  A second aspect of the present invention is an invention based on the first aspect, wherein the holder member of the holder receives the projecting vertex of the lowermost part of the polygonal plate-shaped molded body, and a pair of main parts of the molded body. One of the surfaces is received by a support member of the holder.

  A third aspect of the present invention is an invention based on the second aspect, and is characterized in that the angle θ of the surface that receives the molded body of the support member with respect to the horizontal plane is 70 to 90 degrees.

  According to a fourth aspect of the present invention, when the polygonal plate-shaped molded body is fired, the molded body is held in a state where the molded body is held up so that any protruding vertex of the molded body faces downward in the vertical direction. It is a holding tool.

  A fifth aspect of the present invention is an invention based on the fourth aspect, wherein the holder further receives a projecting apex at the bottom of the polygonal plate-like molded body, and a pair of the molded body And a support member that receives one of the main surfaces.

  A sixth aspect of the present invention is the invention based on the fifth aspect, and is characterized in that the angle θ of the surface that receives the molded body of the support member with respect to the horizontal plane is 70 to 90 degrees.

  In the firing method according to the first aspect of the present invention or the holder according to the fourth aspect, the molded body is held so that any protruding vertex of the molded body formed in a polygonal plate shape is vertically downward. Since it is fired in a state where it is held upright, the contact area between the polygonal plate-shaped molded body and the holder is extremely small, and even if the molded body shrinks during firing, the sintered body shrinks quickly with almost no friction. . As a result, no cracks occur in the sintered body. Moreover, it is not necessary to use a hydrostatic pressure press (CIP) or the like that increases the number of steps for producing a molded body as in the conventional method for producing a ceramic target, so that the process for producing a rectangular plate-like molded body is simplified. Can be In addition, the rectangular plate-shaped molded body shrinks during firing, but since this molded body is in contact with the holder in an extremely small area, the gas can be discharged from the molded body relatively smoothly, and the occurrence of color unevenness can be suppressed. At the same time, the density of the sintered body can be improved. Furthermore, since the contact area between the molded body and the holder during firing is extremely small, the temperature rising rate of the molded body and the temperature lowering rate of the sintered body during firing can be greatly increased. As a result, a sintered body can be obtained by firing the molded body with relatively little energy.

  In the firing method according to the second aspect of the present invention or the holder according to the fifth aspect, the holder member receives substantially the entire weight of the polygonal plate-like molded body in a small area, and the support member is one of the molded bodies. Since the main surface is received with an extremely small pressure, the molded body is fired in a flat state, and the molded body does not fall down unintentionally, and a sintered body without warping can be obtained. In addition, the square plate-shaped molded body contacts the holder member with a very small area but with a very small area, and contacts the support member with a large area but with a very small pressure. Even so, the molded body quickly shifts with respect to the support member, and the gas escapes from the molded body relatively smoothly. As a result, cracks do not occur in the molded body, generation of color unevenness can be suppressed, and the density of the sintered body can be improved.

It is the sectional view on the AA line of FIG. 2 which shows the state which hold | maintains the square-plate-shaped molded object with the holder of 1st Embodiment of this invention. It is the BB sectional view taken on the line of FIG. It is CC sectional view taken on the line of FIG. 4 which shows the state holding the square-plate-shaped molded object with the holder of 2nd Embodiment of this invention. It is the DD sectional view taken on the line of FIG. 10 is a perspective view showing a state in which a rectangular plate-shaped molded body is held by a holder of Comparative Example 5. FIG. It is the EE sectional view taken on the line of FIG. 10 is a perspective view showing a state in which a rectangular plate-like molded body is held by a holder of Comparative Example 6. FIG. It is the FF sectional view taken on the line of FIG.

Next, an embodiment for carrying out the present invention will be described with reference to the drawings.
<First Embodiment>
As shown in FIGS. 1 and 2, when the molded body 11 is fired in a firing furnace, the molded body 11 is held by a holder 12. In this embodiment, the molded body 11 is obtained by spray-drying a slurry prepared by mixing a metal oxide powder, a binder, and an organic solvent to obtain a mixed granulated powder, and then molding the granulated powder. And formed into a square plate by molding at a predetermined pressure (uniaxial press molding or the like). In addition, the holder 12 is configured to hold the molded body 11 in a standing state so that any protruding vertex of the molded body 11 faces downward in the vertical direction when firing the rectangular plate-shaped molded body 11. The Specifically, the holder 12 includes a holder member 13 that receives the projecting apex at the bottom of the rectangular plate-shaped molded body 11, and a support member that receives one main surface of the pair of main surfaces of the molded body 11. 14.

  The holder member 13 has a rectangular parallelepiped base portion 13a and a receiving portion 13b protruding upward at the center of the horizontal upper surface of the base portion 13a. The base portion 13a and the receiving portion 13b are integrally formed of an oxide-based porous ceramic such as alumina or magnesia, or a non-oxidizing porous ceramic such as silicon carbide or silicon nitride. A substantially V-shaped notch 13c is formed in the center of the upper surface of the receiving part 13b, and the projecting vertex of the lowermost part of the molded body 11 is accommodated in the notch 13c. The opening angle α of the notch 13c is formed to be substantially the same as the angle of the protruding vertex at the bottom of the molded body 11. The interval H between the upper ends of the notches 13c is 5 to 60%, preferably 10 to 30% of the length of the diagonal line intersecting the vertical plane including the projecting apex at the bottom of the rectangular plate-shaped molded body 11. Is set in the range. Here, the interval H is limited to the range of 5 to 60% of the length of the diagonal line intersecting the vertical plane including the projecting vertex at the bottom of the molded body 11. This is because it cannot be stably held, and if it exceeds 60%, the contact area between the holder member 13 and the molded body 11 becomes too large and cracks occur in the sintered body after firing. Furthermore, the angle θ with respect to the vertical line of the bottom of the notch 13c is set to 70 to 90 degrees, preferably 75 to 85 degrees. This is because the angle θ with respect to the vertical line of the bottom of the notch 13 c is made the same as the angle θ with respect to the horizontal plane of the surface of the support member 14 that receives the molded body 11, and the bottom of the notch 13 c is the lowermost part of the molded body 11. This is because the side including the protruding vertex is received with uniform pressure.

  The support member 14 has a fixed portion 14a fixed to the upper surface of the base portion 13a by a bolt 16, and an upright portion 14b erected from the fixed portion 14a. The fixed portion 14a and the upright portion 14b are integrally formed of an oxide-based porous ceramic such as alumina or magnesia, or a non-oxidizing porous ceramic such as silicon carbide or silicon nitride. As described above, the angle θ of the surface of the upright portion 14b that receives the molded body 11 with respect to the horizontal plane is set to 70 to 90 degrees, preferably 75 to 85 degrees. That is, the angle formed by the receiving surface of the molded body 11 of the upright portion 14b and the lower surface of the fixed portion 14a is θ. Here, the angle θ with respect to the horizontal plane of the surface that receives the molded body 11 of the upright portion 14b is limited to the range of 70 to 90 degrees. If the angle θ is less than 70 degrees, the pressure that receives the molded body 11 of the raised section 14b becomes too large. When the molded body 11 contracts during firing, the molded body 11 may not be quickly displaced with respect to the upright portion 14b, and the sintered body may be cracked or uneven in color. It is because the molded object 11 will fall if it exceeds.

  The orientation of the notch 13c is preferably changed according to the position of the center of gravity G of the molded body 11. That is, the orientation of the notch 13c is set so that the center of gravity G of the molded body 11 is located in the vertical plane including the lower side of the notch 13c. Specifically, when the molded body 11 has a square plate shape, the orientation of the cutout portion 13c is set upward, and when the molded body 11 has a rectangular plate shape, the orientation of the cutout portion 13c is Set diagonally upward. As a result, the molded body 11 is held by the holder 12 in a state where the left and right balance of the main surface is maintained.

  A method for firing the rectangular plate-shaped molded body 11 using the holder 12 configured as described above will be described. First, the projecting vertex of the lowermost portion of the rectangular plate-shaped molded body 11 is inserted into the notch 13c of the holder member 13, and the molded body 11 is in a state where one main surface of the molded body 11 is in contact with the support member 14. Is fired, the receiving portion 13b of the holder member 13 receives substantially the entire weight of the molded body 11 in a narrow area, and the upright portion 14b of the support member 14 receives one main surface of the molded body 11 with a very small pressure. As a result, the molded body 11 is fired in a state of being maintained in a flat plate state, and the molded body 11 does not fall down unintentionally, and a sintered body without warping can be obtained. In addition, the quadrangular plate-shaped molded body 11 is in contact with the receiving portion 13b with a very small area although having a large pressure, and is in contact with the standing portion 14b with a very small pressure although having a large area. Even if the body 11 contracts, the molded body 11 quickly shifts with respect to the standing portion 14b, and the gas escapes from the molded body 11 relatively smoothly. As a result, cracks do not occur in the molded body 11, the occurrence of color unevenness can be suppressed, and the density of the sintered body can be improved. Furthermore, in this embodiment, the molded body 11 can be produced by uniaxial press molding or the like with less man-hours without using a hydrostatic press (CIP) or the like that increases the number of steps for producing the molded body 11. 11 can be simplified.

<Second Embodiment>
3 and 4 show a second embodiment of the present invention. 3 and 4, the same reference numerals as those in FIGS. 1 and 2 denote the same components. In this embodiment, the angle θ of the upper surface of the base 53a of the holder member 53 with respect to the horizontal plane is set to 70 to 90 degrees, preferably 75 to 85 degrees. The angle of the bottom of the notch 53c with respect to the vertical line is also set to be the same as the angle θ with respect to the horizontal plane of the upper surface of the base 53a. On the other hand, in the support member 54, the angle formed between the receiving surface of the molded body 11 of the standing portion 54b and the lower surface of the fixed portion 54a is set to be a right angle (90 degrees). This is because when the support member 54 is attached to the upper surface of the base portion 53a, the angle θ of the surface that receives the molded body 11 of the standing portion 54b with respect to the horizontal plane is 70 to 90 degrees, preferably 75 to 85 degrees. It is. The configuration other than the above is the same as that of the first embodiment.

  In the holder 52 configured as described above, the receiving portion 53b and the support member 54 are relatively simple by setting the angle θ with respect to the horizontal plane of the upper surface of the base portion 53a to 70 to 90 degrees, preferably 75 to 85 degrees. Therefore, it is possible to reduce the manufacturing cost of the mold for manufacturing the holder 52 or reduce the number of processing steps of the holder 52. In addition, the method for firing the rectangular plate-shaped molded body 11 using the holder 52 configured in this manner is substantially the same as that in the first embodiment, and thus the repeated description is omitted.

  In the first and second embodiments, the molded body is formed in a quadrangular plate shape, but may be formed in a triangular plate shape, a pentagonal plate shape, or a hexagonal plate shape or more. Moreover, in the said 1st and 2nd embodiment, although the holder was comprised by the holder member and the support member, when a molded object is comparatively thick, for example, the thickness of a molded object is a triangular plate-shaped molded object. It is 5% or more of the length of the longest diagonal line among the diagonal lines intersecting the vertical line including the projecting vertex at the bottom of the lowermost protruding vertex of the quadrangular or more plate-shaped molded body. In this case, since the molded body hardly falls down in the direction of the main surface, the support member need not be used. In this case, since the molded body is fired in a state where it is held upright by a holder so that any protruding vertex of the molded body formed in a polygonal plate shape is vertically downward, the polygonal plate-shaped molding is performed. The contact area between the body and the holder is extremely small, and even if the molded body shrinks during firing, the sintered body shrinks quickly with almost no friction. As a result, no cracks occur in the sintered body. In addition, the rectangular plate-shaped molded body shrinks during firing, but since this molded body is in contact with the holder in an extremely small area, the gas can be discharged from the molded body relatively smoothly, and the occurrence of color unevenness can be suppressed. At the same time, the density of the sintered body can be improved. Furthermore, since the contact area between the molded body and the holder during firing is extremely small, the temperature rising rate of the molded body and the temperature lowering rate of the sintered body during firing can be greatly increased. As a result, a sintered body can be obtained by firing the molded body with relatively little energy.

Next, examples of the present invention will be described in detail together with comparative examples.
<Example 1>
First, a mixed powder of zinc oxide powder having an average particle diameter of 3 μm and gallium oxide powder having an average particle diameter of 2 μm is subjected to uniaxial press molding (pressure: 100 MPa), and squares having a length, width and thickness of 180 mm, 250 mm and 15 mm, respectively. Five plate-shaped compacts were produced. The average particle size of zinc oxide powder or gallium oxide powder is determined by using a FRA type manufactured by Nikkiso Co., Ltd. according to a laser diffraction / scattering method (microtrack method), and using sodium hexametaphosphate as a dispersion medium. The value measured three times with a measurement time of 30 seconds was obtained by averaging.

  Next, as shown in FIGS. 1 and 2, the molded body 11 was held by a holder 12. Specifically, the holder 12 includes a holder member 13 that receives the projecting apex at the bottom of the rectangular plate-shaped molded body 11, and a support member that receives one main surface of the pair of main surfaces of the molded body 11. 14. The holder member 13 has a rectangular parallelepiped base portion 13a and a receiving portion 13b protruding upward at the center of the horizontal upper surface of the base portion 13a. The support member 14 is bolted to the upper surface of the base portion 13a. 16 has a fixed portion 14a fixed by 16 and an upright portion 14b erected from the fixed portion 14a. The support member 14 was attached to the holder member 13, and the angle θ with respect to the horizontal plane of the surface that received the molded body 11 of the standing portion 14b at this time was set to 80 degrees. Further, the notch 13c is set upward, the opening angle α is set 90 ° upward, and the interval H between the upper ends of the openings of the notch 13c is a vertical plane including the projecting apex at the bottom of the molded body 11. It was set to 20% of the length of intersecting diagonal lines. Further, in this state, the molded body 11 was placed in a firing furnace together with the holder 12, and held at 1300 ° C. for 5 hours in an air atmosphere to produce five sintered bodies. These sintered bodies were referred to as Example 1.

<Comparative Example 1>
First, three molded bodies (180 mm long, 250 mm wide, 15 mm thick) of the same material and shape as the molded body of Example 1 were produced. Next, in the state where the flat surface (main surface) having the largest area of these molded bodies is in contact with the aluminum oxide floor plate, that is, in the state where the molded body is placed flat on the floor plate, it is placed in a firing furnace. And held at 1300 ° C. for 5 hours to produce three sintered bodies. These sintered bodies were referred to as Comparative Example 1.

<Comparative Example 2>
First, three molded bodies (180 mm long, 250 mm wide, 15 mm thick) of the same material and shape as the molded body of Example 1 were produced. Next, an aluminum oxide bed powder having an average particle size of 0.5 mm was spread on the floor plate. Further, in the state in which the flat surface (main surface) having the widest area of the molded body is in contact with the bed powder, that is, in the state where the molded body is placed flat on the bed powder, the molded body is placed in a firing furnace and heated to 1300 ° C. in an air atmosphere. Three sheets of sintered bodies were produced by holding for 5 hours. These sintered bodies were referred to as Comparative Example 2.

<Comparative Example 3>
First, three molded bodies (180 mm long, 250 mm wide, 15 mm thick) of the same material and shape as the molded body of Example 1 were produced. Next, a block made of aluminum oxide (vertical: 180 mm, horizontal: 250 mm, height: 15 mm) was spread on the floor plate. Furthermore, the molded body was placed in a firing furnace in a state where the flat surface (main surface) having the largest area was in contact with the block, that is, in a state where the molded body was placed flat on the block, and was heated at 1300 ° C. for 5 hours in an air atmosphere. Holding, three sintered bodies were produced. These sintered bodies were referred to as Comparative Example 3.

<Comparative example 4>
First, three molded bodies (180 mm long, 250 mm wide, 15 mm thick) of the same material and shape as the molded body of Example 1 were produced. Next, this molded body was placed in a firing furnace in a state in which the lateral side surface (surface having a width of 250 mm × thickness of 15 mm) was brought into contact with the floor plate, that is, the molded body was placed in a horizontally long state on the floor plate. Three sintered bodies were produced by holding at 1300 ° C. for 5 hours. These sintered bodies were referred to as Comparative Example 3.

<Comparative Example 5>
First, a holder 2 as shown in FIGS. 5 and 6 was produced. The holder 2 is made of an aluminum oxide floor plate 2a, and an oxide film provided on the floor plate 2a with a long interval of 220 mm in the vertical direction and a short interval of 20 mm in the horizontal direction. And four pillar members 2b made of aluminum. The cross section of the column member 2b was a square having a side of 10 mm. Next, seven molded bodies 11 (length 180 mm, width 250 mm, thickness 15 mm) of the same material and shape as the molded body 11 of Example 1 were produced. Further, in a state where the lateral side surfaces (surfaces of 250 mm wide × 15 mm thick) of these molded bodies 11 are in contact with the floor plate 2a, that is, in a state where the molded body 11 is placed on the floor plate 2a in a horizontally long state, The four pillar members 2b were loosely inserted within a short interval. At this time, since the short interval (20 mm) between the four column members 2b is formed slightly wider than the thickness (15 mm) of the molded body 11, two main surfaces of the molded body 11 are opposed to this surface. The column member 2b was brought into surface contact. In this state, the molded body 11 was placed in a firing furnace together with the holder 2, and held at 1300 ° C. for 5 hours in an air atmosphere to produce seven sintered bodies. These sintered bodies were referred to as Comparative Example 5. 5 and 6, the single molded body 11 is held by the holder 2, but in reality, two pillar members having a long interval of 220 mm in the vertical direction are placed on the floor plate in the horizontal direction. Eight positions (total number of column members: 16) were set up at a short interval of 20 mm in the direction so that seven molded bodies could be held respectively.

<Comparative Example 6>
First, a holder 7 as shown in FIGS. 7 and 8 was produced. The holder 7 is made of an aluminum oxide floor plate 7a, and an oxidation plate provided on each corner of the rectangle with a long space of 220mm in the vertical direction and a short space of 40mm in the horizontal direction on the floor plate 7a. There are provided four column members 7b made of aluminum and four erection members 7c made of aluminum oxide spanned over these column members 7b. Two of the four erected members 7c were spanned across two of the four column members 7b spaced apart so as to be spaced apart in the vertical direction and extended in the horizontal direction. The remaining two erection members 7c were stretched over the remaining two column members 7b so as to be spaced apart in the vertical direction and extended in the horizontal direction. At this time, the four erection members 7c were spanned so as to be located inside the short interval of the four column members 7b, and the horizontal interval between the erection members 7c was 20 mm. The cross section of the column member 7b was a square having a side of 10 mm, and the cross section of the erection member 7c was a circle having a diameter of 10 mm. Next, seven molded bodies 11 (length 180 mm, width 250 mm, thickness 15 mm) of the same material and shape as the molded body 11 of Example 1 were produced. Further, in a state where the lateral side surfaces (surfaces of 250 mm wide × 15 mm thick) of these molded bodies 11 are in contact with the floor plate 7 a, that is, in a state where the molded body 11 is set up horizontally on the floor board 7 a, It was loosely inserted between the four construction members 7c. At this time, since the horizontal interval (20 mm) of the erection member 7 c is formed slightly wider than the thickness (15 mm) of the molded body 11, two main surfaces of the molded body 11 are opposed to this surface. Line contact was made with the erection member 7c. In this state, the molded body 11 was placed in a firing furnace together with the holder 7 and held at 1300 ° C. for 5 hours in an air atmosphere to prepare seven sintered bodies. These sintered bodies were referred to as Comparative Example 6. 7 and 8, one molded body 11 is held by the holder 7, but in reality, two column members having a long interval of 220 mm in the vertical direction are placed on the floor plate in the horizontal direction. Standing at 8 locations (total number of column members: 16) with a short interval of 40 mm in the direction, and spanning the four construction members so as to be located inside the short spacing of the pillar members (construction The total number of members: 28) and 7 molded bodies can be held respectively.

<Comparative test 1 and evaluation>
The cracks, warpage, density, and color unevenness of the sintered bodies of Examples 1 to 5 and Comparative Examples 7 and 8 were measured. The cracks and color unevenness of the sintered body were measured visually. The warpage of the sintered body was a value (%) obtained by dividing the maximum amount of warpage in the thickness direction of the maximum surface of the sintered body by the thickness of the sintered body and then multiplying by 100. Further, the density of the sintered body was measured by a volume method. These results are shown in Table 1. In addition, the curvature of the sintered compact in Table 1 was taken as the largest value among the maximum values for every sintered compact. Moreover, the density of the sintered compact in Table 1 was made into the average (arithmetic mean) value of the value of each sintered compact.

表１から明らかなように、比較例１〜３の焼結体には割れが発生したのに対し、実施例１及び比較例４〜６の焼結体には割れは発生しなかった。また、比較例１〜６の焼結体では反りが４〜２０％と大きかったのに対し、実施例１の焼結体では反りが０．８％と小さかった。また、比較例１〜６の焼結体では密度が９２．０〜９８．０％と小さかったのに対し、実施例１の焼結体では密度が９８．４％と大きかった。更に比較例１〜３の焼結体では接触面に色ムラが発生したのに対し、実施例１及び比較例４〜６の焼結体では、色ムラが発生しなかった。

As apparent from Table 1, cracks occurred in the sintered bodies of Comparative Examples 1 to 3, whereas no cracks occurred in the sintered bodies of Example 1 and Comparative Examples 4 to 6. Further, in the sintered bodies of Comparative Examples 1 to 6, the warp was as large as 4 to 20%, whereas in the sintered body of Example 1, the warp was as small as 0.8%. Moreover, in the sintered bodies of Comparative Examples 1 to 6, the density was as small as 92.0 to 98.0%, whereas in the sintered body of Example 1, the density was as large as 98.4%. Furthermore, while the sintered bodies of Comparative Examples 1 to 3 were uneven in color on the contact surface, the sintered bodies of Example 1 and Comparative Examples 4 to 6 were not uneven in color.

<Example 2>
Five sintered bodies were produced in the same manner as in Example 1 except that the angle θ with respect to the horizontal plane of the surface receiving the molded body of the upright portion was set to 70 degrees. These sintered bodies were referred to as Example 2.
<Example 3>
Five sintered bodies were produced in the same manner as in Example 1 except that the angle θ with respect to the horizontal plane of the surface receiving the molded body of the standing portion was set to 90 degrees. These sintered bodies were referred to as Example 3.
<Example 4>
Five sintered bodies were produced in the same manner as in Example 1 except that the angle θ with respect to the horizontal plane of the surface receiving the molded body of the standing portion was set to 85 degrees (preferred lower limit value of the angle). These sintered bodies were referred to as Example 4.
<Example 5>
Five sintered bodies were produced in the same manner as in Example 1 except that the angle θ with respect to the horizontal plane of the surface receiving the molded body of the standing portion was set to 75 degrees (preferred upper limit value of the angle). These sintered bodies were referred to as Example 5.

<Comparative Example 7>
Five sintered bodies were produced in the same manner as in Example 1 except that the angle θ with respect to the horizontal plane of the surface receiving the molded body of the standing portion was set to 65 degrees (an angle slightly lower than the lower limit value). These sintered bodies were referred to as Comparative Example 7.
<Comparative Example 8>
Five sintered bodies were produced in the same manner as in Example 1 except that the angle θ with respect to the horizontal plane of the surface receiving the molded body of the standing portion was set to 91 degrees (an angle slightly exceeding the upper limit value). These sintered bodies were referred to as Comparative Example 8.

<Comparative test 2 and evaluation>
The stability of the molded bodies during firing in Examples 1 to 5 and Comparative Examples 7 and 8, and cracks, warpage, density, and color unevenness of these sintered bodies were measured. The stability of the molded body was evaluated based on an angle at which the molded body started to fall when the surface receiving the molded body was tilted with respect to a horizontal plane. Table 2 shows how many times the angle is set based on the angles set in the examples and comparative examples. The larger the angle, the higher the limit of collapse due to vibration during the firing process and shrinkage movement during sintering. The tilt speed was 1 degree / 10 seconds. Further, cracks, warpage, density and color unevenness of the sintered body were measured in the same manner as in Comparative Test 1. The results are shown in Table 2.

表２から明らかなように、比較例８の焼結体には割れが発生したのに対し、実施例１〜５の焼結体には割れは発生しなかった。また比較例７の焼結体では反りが１２％と大きかったのに対し、実施例１〜５の焼結体では反りが０．６〜２．２％と小さかった。また比較例７の焼結体では密度が９７．０％と小さかったのに対し、実施例１〜５の焼結体では密度が９８．４〜９９．０％と大きかった。更に比較例７の焼結体では敷板との接触面に色ムラが発生したのに対し、実施例１〜５の焼結体では色ムラが発生しなかった。

As apparent from Table 2, cracks occurred in the sintered body of Comparative Example 8, whereas no cracks occurred in the sintered bodies of Examples 1 to 5. The warpage of the sintered body of Comparative Example 7 was as large as 12%, whereas the warpage of the sintered bodies of Examples 1 to 5 was as small as 0.6 to 2.2%. The density of the sintered body of Comparative Example 7 was as small as 97.0%, whereas the density of the sintered bodies of Examples 1 to 5 was as large as 98.4 to 99.0%. Furthermore, in the sintered body of Comparative Example 7, color unevenness occurred on the contact surface with the base plate, whereas in the sintered bodies of Examples 1 to 5, no color unevenness occurred.

<Example 6>
Similar to Example 1, except that the interval H between the upper ends of the openings of the notches is set to 5% (lower limit) of the length of the diagonal line intersecting the vertical plane including the projecting vertex at the bottom of the molded body. Thus, five sintered bodies were produced. These sintered bodies were referred to as Example 6.
<Example 7>
Similar to Example 1, except that the interval H between the upper ends of the openings of the notches is set to 60% (upper limit) of the length of the diagonal line intersecting the vertical plane including the projecting vertex at the bottom of the molded body. Thus, five sintered bodies were produced. These sintered bodies were referred to as Example 7.
<Example 8>
Example, except that the interval H between the upper ends of the openings of the notches was set to 10% (the lower limit value of the preferred range) of the length of the diagonal line intersecting the vertical plane including the projecting vertex at the bottom of the molded body In the same manner as in Example 1, five sintered bodies were produced. These sintered bodies were referred to as Example 8.
<Example 9>
Example, except that the interval H at the upper end of the opening of the notch is set to 30% (the upper limit value of the preferred range) of the diagonal line intersecting the vertical plane including the projecting vertex at the bottom of the molded body In the same manner as in Example 1, five sintered bodies were produced. These sintered bodies were referred to as Example 9.

<Comparative Example 9>
Except that the interval H between the upper ends of the openings of the notches is set to 3% of the length of the diagonal line intersecting the vertical plane including the projecting vertex at the bottom of the molded body (an angle slightly lower than the lower limit value), Five sintered bodies were produced in the same manner as in Example 1. These sintered bodies were referred to as Comparative Example 9.
<Comparative Example 10>
Except that the interval H between the upper ends of the openings of the notches is set to 70% of the length of the diagonal line intersecting the vertical plane including the projecting vertex at the bottom of the molded body (an angle slightly exceeding the upper limit), Five sintered bodies were produced in the same manner as in Example 1. These sintered bodies were referred to as Comparative Example 10.

<Comparative test 3 and evaluation>
The stability of the molded bodies during firing in Examples 1, 6 to 9 and Comparative Examples 9 and 10, and cracks, warpage, density, and color unevenness of these sintered bodies were measured. The stability of the molded body was evaluated based on an angle at which the molded body started to fall when the surface receiving the molded body was tilted with respect to a horizontal plane. Table 2 shows how many times the angle is set based on the angles set in the examples and comparative examples. The larger the angle, the higher the limit of collapse due to vibration during the firing process and shrinkage movement during sintering. The tilt speed was 1 degree / 10 seconds. Further, cracks, warpage, density and color unevenness of the sintered body were measured in the same manner as in Comparative Test 1. The results are shown in Table 3.

表３から明らかなように、比較例９の焼結体には切欠き部にクラックが発生したのに対し、実施例１及び６〜９の焼結体には割れは発生しなかった。また比較例１０の焼結体では密度が９７．６％と小さかったのに対し、実施例１及び６〜９の焼結体では密度が９８．２〜９８．６％と大きかった。

As is clear from Table 3, cracks occurred in the notches in the sintered body of Comparative Example 9, whereas no cracks occurred in the sintered bodies of Examples 1 and 6-9. The density of the sintered body of Comparative Example 10 was as small as 97.6%, whereas the density of the sintered bodies of Examples 1 and 6 to 9 was as large as 98.2 to 98.6%.

11 Molded body 12,52 Holder 13,53 Holder member 14,54 Support member

Claims (6)

In a method for producing a plate-like sintered body by firing a plate-like molded body in a firing furnace,
The molded body is formed in a polygonal plate shape,
Firing the molded body in a state where the molded body is held upright and held by a holder so that any protruding vertex of the molded body is vertically downward.   2. The holder member of the holder receives the projecting vertex of the lowermost part of the polygonal plate-shaped molded body, and the support member of the holder receives one main surface of the pair of main surfaces of the molded body. A method for firing the green body.   The method according to claim 2, wherein an angle θ of a surface of the support member that receives the molded body with respect to a horizontal plane is 70 to 90 degrees.   A holder for firing a molded body that holds the molded body in an upright state so that any protruding vertex of the molded body faces downward in the vertical direction during firing of the polygonal plate-shaped molded body.   The holder is provided with a holder member that receives the projecting vertex of the lowermost portion of the polygonal plate-shaped molded body, and a support member that receives one main surface of the pair of main surfaces of the molded body. A holder for firing the green body.   6. The holder for firing a molded body according to claim 5, wherein an angle [theta] of the surface of the support member that receives the molded body with respect to a horizontal plane is 70 to 90 degrees.

Images